使用RabbitMQ发送对象

问题描述

我明白这个问题在
重复问题

如果使用第一种方式执行此操作

if to do this using the first way

我有以下内容跟踪：

java.io.EOFException
at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2304)
at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2773)
at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:798)
at java.io.ObjectInputStream.<init>(ObjectInputStream.java:298)
at com.mdnaRabbit.worker.data.Data.fromBytes(Data.java:78)
at com.mdnaRabbit.worker.App.main(App.java:41)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

我检查并确保该消息在发送者类中完全转换为字节，但消费者无法接收它。

I've checked and shure that message is transformd to bytes absolutely well in sender class, but the consumer can't receive it.

这里是我的生产者类：

package com.mdnaRabbit.newt;

import java.io.IOException;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.MessageProperties;
import org.apache.commons.lang.SerializationUtils;
import com.mdnaRabbit.worker.data.Data;

public class App {

    private static final String TASK_QUEUE_NAME = "task_queue";

    public static void main( String[] argv) throws IOException{

        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);

        int i = 0;

        do {
            Data message = getMessage();
            byte [] byteMessage = message.getBytes();
            //System.out.println(byteMessage);
            channel.basicPublish("", TASK_QUEUE_NAME, MessageProperties.PERSISTENT_TEXT_PLAIN, byteMessage);
            System.out.println(" [" + (i+1) + "] message Sent" + Data.fromBytes(byteMessage).getBody());
            i++;
        } while (i<15);

        channel.close();
        connection.close();
    }

    private static Data getMessage(){
        Data data = new Data();
        data.setHeader("header");
        data.setDomainId("abc.com");
        data.setReceiver("me");
        data.setSender("he");
        data.setBody("body");
        return data;
    }

    private static String joinStrings(String[] strings, String delimiter){
        int length = strings.length;
        if (length == 0) return "";
        StringBuilder words = new StringBuilder(strings[0]);
        for (int i = 1; i < length; i++){
            words.append(delimiter).append(strings[i]);
        }
        return words.toString();
    }
}

这是我的消费者类：

    package com.mdnaRabbit.worker;

import java.io.IOException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.QueueingConsumer;
import com.mdnaRabbit.worker.data.Data;
import org.apache.commons.lang.SerializationUtils;

public class App {

    private static final String TASK_QUEUE_NAME = "task_queue";
    private static int i = 0;
    public static void main( String[] argv )
            throws IOException,
            InterruptedException{

        ExecutorService threader = Executors.newFixedThreadPool(20);
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection(threader);
        final Channel channel = connection.createChannel();

        channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        channel.basicQos(20);

        final QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(TASK_QUEUE_NAME, false, consumer);

        try {

            while (true) {

                        try {QueueingConsumer.Delivery delivery = consumer.nextDelivery();
                            Data message = Data.fromBytes(delivery.getBody());
                            //Data message = (Data) SerializationUtils.deserialize(delivery.getBody());

                            System.out.println(" [" + (i++) +"] Received" + message.getBody());

                            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
                        }catch (Exception e){
                        }
                    }
        } catch (Exception e){
            e.printStackTrace();
        }
        channel.close();
        connection.close();
    }

}

这是我的数据类：

package com.mdnaRabbit.worker.data;

import java.io.*;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Data implements Serializable{

    public String header;
    public String body;
    public String domainId;
    public String sender;
    public String receiver;

    public void setHeader(String head){
        this.header = head;
    }

    public String getHeader(){
        return header;
    }

    public void setBody(String body){
        this.body = body;
    }

    public String getBody(){
        return body;
    }

    public void setDomainId(String domainId){
        this.domainId = domainId;
    }

    public String getDomainId(){
        return domainId;
    }

    public void setSender(String sender){
        this.sender = sender;
    }

    public String getSender(){
        return sender;
    }

    public String getReceiver(){
        return receiver;
    }

    public void setReceiver(String receiver){
        this.receiver = receiver;
    }


    public byte[] getBytes() {
        byte[]bytes;
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try{
            ObjectOutputStream oos = new ObjectOutputStream(baos);
            oos.writeObject(this);
            oos.flush();
            oos.reset();
            bytes = baos.toByteArray();
            oos.close();
            baos.close();
        } catch(IOException e){
            bytes = new byte[] {};
            Logger.getLogger("bsdlog").log(Level.ALL, "unable to write to output stream" + e);
        }
        return bytes;
    }

    public static Data fromBytes(byte[] body) {
        Data obj = null;
        try {
            ByteArrayInputStream bis = new ByteArrayInputStream(body);
            ObjectInputStream ois = new ObjectInputStream(bis);
            obj = (Data) ois.readObject();
            ois.close();
            bis.close();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }
        return obj;
    }
}

我似乎总是看到消费者收到消息，因为当我'我没有试图将它转换为对象而只是写
System.out.println（delivery.getBody）
它显示字节

I always seems that consumer receives messages, because when I'm not trying to transform it into the object and just writeSystem.out.println(delivery.getBody)it shows bytes

推荐答案

看起来你收到的字节数组是空的。这是因为：

It looks like the byte array you receive is empty. This happens because of this:

    } catch(IOException e){
        bytes = new byte[] {};
    }

当产生异常时，代码不会警告你有什么东西是坏了，只是发送一个空数组。 您至少应该记录错误。

When an exception is produced, the code doesn't warn you that something is broken and just sends an empty array instead. You should at least log the error.

正在生成异常可能是因为您尝试序列化不可序列化的类。要使类可序列化，您必须在其声明中添加implements Serializable：

The exception is being produced probably because you are trying to serialize a class that is not serializable. To make a class serializable you have to add "implements Serializable" to its declaration:

public class Data implements Serializable {

这篇关于使用RabbitMQ发送对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！